body {
    font-family: 'Arial', sans-serif;
    margin: 20px;
    background-color: #f0f2f5;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 20px;
    background: white;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

h1 {
    color: #1a73e8;
    text-align: center;
    margin-bottom: 30px;
}

.controls {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
}

select {
    padding: 8px 12px;
    border: 1px solid #dadce0;
    border-radius: 4px;
    font-size: 16px;
    flex-grow: 1;
}

button {
    padding: 8px 16px;
    background: #1a73e8;
    color: white;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    transition: background 0.2s;
}

button:hover {
    background: #1557b0;
}

.problem-item {
    margin: 10px 0;
    padding: 15px;
    border: 1px solid #eee;
    border-radius: 4px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.problem-text {
    min-width: 120px;
    font-size: 16px;
}

input[type="number"] {
    padding: 6px 8px;
    border: 1px solid #dadce0;
    border-radius: 4px;
    width: 100px;
    font-size: 14px;
}

.correct {
    background: #e6f4ea;
    border-color: #34a853;
}

.wrong {
    background: #fce8e6;
    border-color: #ea4335;
}

.missing {
    background: #f8f9fa;
    border-color: #dadce0;
}

#score {
    margin-top: 20px;
    padding: 10px;
    background: #f8f9fa;
    border-radius: 4px;
    text-align: center;
    font-weight: bold;
    color: #1a73e8;
}